CALR and rheumatoid arthritis: As shown in Fig. 3B, this RA Ab confirmed the binding toward hrCRT in Western blot, whereas not only RA-rmAbs with no binding to RA-FLS in cell-based immune screening but also other RA-FLS–reactive RA-rmAbs failed to recognize CRT in Western blot (Fig. 3C, Supplemental Fig. 3, respectively).